IceCube. Flasher Board. Engineering Requirements Document (ERD)

Size: px

Start display at page:

Download "IceCube. Flasher Board. Engineering Requirements Document (ERD)"

Herbert Walker
5 years ago
Views:

1 IceCube Flasher Board Engineering Requirements Document (ERD) AK 10/1/2002 Version 0.00 NK 10/7/ a 10/8/ b 10/10/ c 0.00d 11/6/ After AK, KW phone conf. 11/12/ a 12/10/ b Note: AK = Albrecht Karle NK = Nobuyoshi Kitamura KW = Kurt Woschnagg Page 1 of 13

2 Table of Contents 1 GENERAL Scope Purpose Precedence Authority Responsibilities Records Units Definitions FUNCTIONAL OVERVIEW General Required Components and Functions Optical Flasher Digital Board ID Device User Devices Passive PMT HV Base Support Devices PERFORMANCE REQUIREMENTS Electrical and Electro-optical Power Electrical Connections Digital Commands Optical Flasher Digital Board ID Device Physical General PCB Dimensions LED Mounting Requirements User Device Area PCB Material Component Placement Minimum Trace Rules Conformal Coating Other PCB Requirements Environmental Temperature Pressure...13 Page 2 of 13

3 3.4 Miscellaneous REFERENCES Page 3 of 13

4 1 GENERAL 1.1 Scope This IceCube Engineering Requirements Document (ERD) specifies the physical, functional and performance requirements of the Flasher Board. 1.2 Purpose This ERD is applicable to the development, prototyping, testing, and verification of the Flasher Board. 1.3 Precedence In the event of a conflict between the provisions of this document and any prior IceCube documentation, the provisions in this document shall supersede. Conflicts between this and non-icecube documents shall be resolved by the Change Control Board. 1.4 Authority Approval of this document for initial release and the subsequent revisions are authorized only by the Change Control Board. 1.5 Responsibilities (a) Physics/Engineering is responsible for writing and updating these requirements to ensure they are correct, complete and current. (b) Quality Assurance is responsible for ensuring this document and changes to it are properly reviewed, approved and maintained. 1.6 Records Records of initial review, approval and changes (Engineering Change Notices, ECN s) in design shall be maintained according to the established processes. 1.7 Units Weights and measures in this document are expressed in the MKS International System of Units (SI). 1.8 Definitions CCB DOM DOMMB DAQ ECN ERD FWHM HV Change Control Board Digital Optical Module Digital Optical Module Main Board Data Acquisition Engineering Change Notice Engineering Requirements Document Full-Width-at-Half-Maximum High Voltage Page 4 of 13

5 IDC Insulation Displacement Connector ns Nano-second (10-9 s) OM Optical Module PCB Printed Circuit Board PE Photoelectron PMT Photomultiplier Tube 2 FUNCTIONAL OVERVIEW 2.1 General The Flasher Board is a modular PCB component to be integrated into each of the Digital Optical Modules. Justification: That each DOM will house a Flasher Board was decided at the In-Ice Devices Meeting at UW (August 2002). The Flasher Board has electrical connections with the Digital Optical Module Main Board (DOMMB). The Flasher Board receives electrical power from the DOMMB. The Flasher Board and the DOMMB communicate via a serial digital link. 2.2 Required Components and Functions Optical Flasher Each Flasher Board has light-emitting diodes (LED s) arranged at the specified PCB locations (See 3.2) for the purpose of generating the optical flash described below. The Flasher Board generates optical flashes using the LED s at timings specified by the DOMMB. The optical flashes are used for the following purposes: Optical Module (OM) self-calibration Local coincidence and time/space offset calibrations Inter-string calibrations Optical properties verification of the ice Explanation: Uniformity of components is seen as an important goal for IceCube optical sensors and DAQ. It is anticipated, however, that optical flashers will be implemented in more than one design over the IceCube array. Flashers may be produced with different light generators. A self-identification of the flasher board version will be a requirement. It is crucial however, that the communications interface to the DOMMB is well defined and unchanged over the entire production Digital Board ID Device The Flasher Board presents a unique digital code identifying itself to the DOMMB when requested. Page 5 of 13

6 2.2.3 User Devices The Flasher Board provides a board area, electrical connectivity and power for the possible installation of a small circuitry ( user device ) of yet-to-bedefined functionality in order to implement future revisions of the design. Justification: The idea here is that future ideas may lead to wishes, requests for additional instrumentation. Acoustic sensors would be an example of such an instrument Passive PMT HV Base Support Devices The flasher board shall provide a board space for the high-voltage generator and related components, such as DAC, ADC, connectors, etc. (collectively referred to as passive PMT HV Base support devices ) for the PMT HV Base employing a passive resistive bleeder chain. The said board space shall be electrically isolated from the rest of the Flasher Board circuitry. The electrical power consumed by the passive PMTHV Base support devices shall not be part of the Flasher Board power budget. The requirements for the passive PMT HV Base support devices are described in the Supplement to the PMT HV Base Board ERD. Note: The electrical signal interface between the DOMMB and the PMT HV Base will be identical regardless of the PMT HV Base design. In the default requirements, the PMT HV Base is an all-in-one PCB component mounted on the PMT. In the passive approach, defined in the Supplement, the PCB mounted on the PMT will likely contain only the resistive bleeder chain and other passive components. The passive PMT HV Base support devices could be implemented through the user device mechanism; however, doing so will make the PMT HV Base design non-transparent to the DOMMB. Page 6 of 13

7 3 PERFORMANCE REQUIREMENTS 3.1 Electrical and Electro-optical Power Power source The Flasher Board shall receive electrical power from the DOMMB Default power source The default power source provided by the DOMMB shall be a ±5 VDC voltage source with a voltage uncertainty of ±5% Optional power source There shall be an unregulated power source of 100 VDC provided by the DOMMB Power dissipation The maximum power dissipation of the Flasher Board drawn from the default power source shall be 110 mw. Status: Currently (11/12/02) the DOMMB design assumes that the Flasher Board takes 110mW. It is likely that the total power consumption of the Flasher Board to exceed 110mW significantly. JP suggests the Flasher Board to have its own on-board DC-DC converter with an input voltage up to 100V ( 11/7/02) Power ON/OFF control The ON/OFF switching of the default power to the Flasher Board shall be established by a one-bit digital signal controlled by the DOMMB. The ON/OFF switching of the optional power shall be controlled by the DOMMB Electrical Connections Ribbon cable The electrical connections between the Flasher Board and the DOMMB shall be facilitated by a 1-mm-pitch IDC ribbon cable with (TBD) conductors. Justification: The small pitch helps reduce the connector footprint on the DOMMB side. Note: If the ribbon cable carries the flasher strobe signal, or any other timingcritical signals, the characteristic impedance of the cable and the connecting PCB traces must be carefully designed. Page 7 of 13

8 Connector The Flasher Board shall have a keyed IDC connector for the ribbon cable specified in the previous paragraph on the PCB location specified in a later section (3.2) Signal assignment Redundancy requirement Each signal, ground and power in the ribbon cable shall have two connector pins allocated to it Connector signal assignment (TBD) Table 3.1 Connector signal assignment Pin # Signal name Explanation 1 DGND Digital & power ground 2 SCLK Serial clock 3 SCLK 4 MOSI Master-out-slave-in 5 MOSI 6 MISO Master-in-slave-out 7 MISO 8 DGND 9 CS0 Chip-select bit 0 10 CS0 11 CS1 Chip-select bit 1 12 CS1 13 CS2 Chip-select bit 2 14 CS2 15 CS3 Chip-select bit 3 16 CS3 17 ON/OFF Power ON/OFF 18 ON/OFF 19 +5V Main power (+) 20 +5V 21 DGND 22 DGND 23-5V Main power (-) 24-5V Main power (-) Digital Commands Digital communication The Flasher Board (Slave device) shall be capable of digitally communicating with the DOMMB (Master device). The said communication shall be in fullduplex with serial clock and four (4) bit address wires. Page 8 of 13

9 On-board devices The following devices on the Flasher Board shall be supported by the digital communication in the previous paragraph: Optical flasher (3.1.4) Digital board ID device (3.1.5) User devices Device address (TBD) The address for the devices on the Flasher Board is as shown in Table 3.2. (This is just a tentative idea.) Table 3.2 Device address Address Device 0000 (reserved) 0001 Optical flasher (Trigger) 0010 Optical flasher (Amplitude) 0011 (reserved) 0100 (reserved) 0101 (reserved) 0110 (reserved) 0111 (reserved) 1001 Digital board ID 1010 (reserved) 1011 (reserved) 1100 (reserved) 1101 (reserved) 1110 (reserved) 1111 (reserved) Page 9 of 13

10 3.1.4 Optical Flasher Functional requirements Operation 1. DOMMB selects one of the Flasher modes 2. DOMMB sets up parameters for the selected mode 3. DOMMB issues a trigger 4. The Flasher fires 5. The Flasher sends timing pulse to the DOMMB 6. The Flasher writes a status code to a register LED requirements General There shall be six (6) identical LED s mounted 60 apart on the periphery of the Flasher Board, as specified in The peak direction of the light emission for each LED shall be met by satisfying the requirements for the mechanical installation of the LED s specified in Peak wavelength The peak wavelength (the wavelength at which the optical output is maximum) shall be in the range of nm. Note: Nichiha NSHU550 has the peak wavelength of 375nm. Longer wavelength LEDs (blue) tend to be available with higher intensity output Maximum ratings The manufacturer s rated maximum operating conditions of the LED s shall be consistent with the rest of the requirements in this document Timing requirements Trigger-to-flash delay The time interval between the optical flash trigger command issued by the DOMMB and the actual emission of the LED light shall be less than 1 µs. Note: GP says this should be more like 10ns, but DJW wants something greater than 1µsec Trigger jitter The trigger-to-flash delay shall not vary more than (TBD) ns from trigger to trigger Trigger spread among the LED s The timing of the flash among all the six LED s shall be within 5 ns Temporal profile The Optical Flasher shall operate either in narrow pulse mode or a wide pulse mode. The two modes are defined by the temporal profile of the light output as follows: Page 10 of 13

11 A. Narrow pulse mode The temporal profile of the light output in narrow pulse mode operation shall be a narrow pulse with the full-width at half the maximum (FWHM) of 15 ns or less. B. Wide pulse mode The temporal profile of the light output in wide pulse mode operation shall be that of a square pulse with the following properties: Rise-time: 30 ns or less Fall-time: 50 ns or less Pulse width: 800±10 ns Intensity: Variable from 1x10 2-2x10 4 photons per ns C. DC mode The Flasher Board shall support operation of the LED s at a constant light level for a minimum of (TBD) sec. Justification: Is this okay for Supernova calibration? Repetition rate The maximum pulse repetition rate of 1 khz shall be supported for both narrow pulse mode and wide pulse mode Intensity requirements Maximum pulse intensity The Flasher Board shall support the maximum peak pulse energy of 5x10 9 photons per pulse. Justification: The intensity requirement corresponds to one (1) photoelectron generated in the OM at 200 m in average ice Minimum pulse intensity The Flasher Board shall support the minimum peak pulse energy of 1x10 3 photons per pulse Adjustability The pulse intensity shall be adjustable by presetting a value via digital communication prior to triggering. The pulse intensity shall be adjustable in logarithmically uniform steps over the minimum required intensity to the maximum required intensity with a minimum of 8-bit resolution (255 steps). Note: We may need only 32 steps Intensity accuracy For a given intensity preset value, the actual output intensity shall vary no more than 15 %. The mean value of the actual output intensity shall vary no more than 3 % per week. Page 11 of 13

12 Spatial profile The light emission shall have a peak in approximately the horizontal direction, where the horizontal plane is defined by the Flasher Board PCB. The emission shall be 50 % of the peak in the directions 30 degrees above and below the horizontal, and 10 % of the peak in the directions 60 degrees above and below the horizontal. Note: It is permissible for the beam to be narrower than this, according to AK Spatial uniformity The optical intensity observed at 3m distance from the center of the Flasher Board (center of the OM?) shall meet the following uniformity requirements: A. Symmetry with respect to the plane of the Flasher Board PCB shall be such that the integrated intensity over the upper hemisphere is to within 20% of that over the lower hemisphere. B. Deviations from a spherical pattern in any direction shall be no greater than 50% Calibrated performance A. Absolute intensity Absolute light output of the maximum intensity pulse shall be known to 20% accuracy by laboratory calibration. B. Linearity The relationship between the actual output intensity versus digital code for intensity adjustment shall be calibrated to within 10 %. Note: The above requirements are adequate for 1. inter-string geometry calibrations 2. linearity measurements 3. verification of the dust structure below 2050m. The linearity and energy measurements will be approached by the bootstrap distance interval calibration, proposed by AK. This method relies on the linearity calibration of the OMs within the specified range from 1 to 200 PE/15ns. While changing the amplitude over 5 orders of amplitude, there are always overlapping regions of linear OMs which can be used to crosscalibrate Electrical (Flasher) Page 12 of 13

13 3.1.5 Digital Board ID Device The digital board ID device shall be a Dallas Semiconductor DS Physical General PCB Dimensions (To be specified by PSL) LED Mounting Requirements User Device Area PCB Material Component Placement Minimum Trace Rules Conformal Coating Conformal coating is required on both sides of the PCB Other PCB Requirements 3.3 Environmental Temperature Both the storage temperature and continuous operating temperature for the Flasher Board shall be in the range of 55 C to +(TBD) C Pressure Both the storage pressure and continuous operating pressure for the Flasher Board shall be in the range of 40,000 Pa to 100,000 Pa. 3.4 Miscellaneous 4 REFERENCES DOMMB-Flasher Board Interface Engineering Requirements Document Digital Optical Module Assembly ERD Page 13 of 13

IceCube. Flasher Board. Engineering Requirements Document (ERD)

IceCube. Flasher Board. Engineering Requirements Document (ERD) IceCube Flasher Board Engineering Requirements Document (ERD) AK 10/1/2002 Version 0.00 NK 10/7/2002 0.00a 10/8/02 0.00b 10/10/02 0.00c 0.00d 11/6/02 0.01 After AK, KW phone conf. 11/12/02 0.01a 12/10/02